Cold rising in a standard temp fridge

So over my years of baking now and your assistance I learned that most of my baking failures were due to under proofing the bread. San Francisco is quite cold all year round so I learned that I could let my sourdoughs bulk rise for over 20 hours followed by a cold proof in the baskets in the fridge worked great.

But yesterday the bulk rise finished and since I couldn't bake this morning here I am after an 18 hour cold proof in the fridge and I want to see if they spring back ok. I didn't cover them and the base of the bread has quite a dry crust of dried dough at the bottom. Should I cut that off? Normally I wouldn't do such a long cold rise because th fridge is in the 30s temperature wise or whatever the standard is.

Is it better to have a longer bulk rise followed by a shorter cold rise ? I've had situations where I put the mostly risen dough in the baskets too early and they continue to rise OUT of the proofing baskets.